The popular image of the business burnout involves somebody who's been busting their hump too hard for too long. It's an image of a somewhat virtuous fatigue, and something brought on by hard, hard work--to the victim's own detriment.

But new research suggests that this is only one version. Your employees (or you, for that matter) might begin showing the sure signs of burnout--exhaustion, cynicism, irritability, and most importantly a lack of productivity--for other reasons, too.

The report, published in the journal PLOS ONE(and recently covered by the Association for Psychological Science) studied 429 employees at an academic institution to analyze patterns in burnt out employees and their coping methods at work. The findings suggest that there are at least three types of burnout.

"Frenetic" burnout is the stereotypical version described above, defined by workers who just have too much on their plate. These employees generally adopt a negative tone, venting about their workload.

"Under-challenged" burnout, however, speaks to employees who plainly feel like they aren't getting much satisfaction out of their work. Employees experiencing this sort of burnout tend to "cognitively avoid" their work, distancing themselves from what they consider an unrewarding experience.

"Worn-out" employees are those who struggle with the stress of the day-to-day and ultimately choose to neglect their work because of those pressures.

The study found that 15 percent of employees in the study experienced frenetic burnout, 9 percent experienced under-challenged burnout, and 21 percent were worn-out.

The study's implications? Primarily, they're a reminder that employees might flame out for reasons other than failure to ensure work-life balance.

Making sure they are facing work that truly engages them--or, alternatively, that you're not putting them too far out of their comfort zone--will also keep employees from developing negative attitudes about their work. And on the hiring front, the concept of under-challenged burnout points to the potential issues with hiring overqualified candidates for vacant positions.